1. Field of the Invention
The present invention relates to a system for introducing, segregating and transporting samples to be analyzed, such as industrial or biological samples, through a conduit.
2. Brief Description of the Prior Art
Automated apparatus for the analysis of liquid samples as a flowing stream was disclosed in U.S. Pat. Nos. 2,797,149 and 2,879,141, both assigned to the instant assignee. In this basic apparatus, the liquid samples are sequentially aspirated from containers located on a turntable arrangement and into a conduit, each sample being separated from the next successive sample by a segment of air. Customarily, the conduit is made of glass, rubber or polyvinylchloride. As the aqueous liquid samples wet the inner surface of the conduit, a residue or thin film of sample liquid adheres to the surface during passage along the conduit. This adhered liquid film is, in part, taken up by the next successive liquid segment, which is thereby contaminated. Various expedients have been successfully utilized to reduce this intersegment contamination.
U.S. Pat. No. 3,479,141, assigned to the instant assignee, discloses an automated analytical apparatus wherein a series of aqueous liquid samples are processed as a flowing stream with substantially no contamination between samples by the mixing of a portion of a prior sample with a succeeding sample (carryover). In such apparatus, a liquid, which is immiscible with the liquid samples and which preferentially wets the interior conduit wall, is referred to as a carrier fluid and is used to pass the successive samples along the conduit. The individual samples are encapsulated in the immiscible liquid and do not contact the conduit wall, whereby no sample residue adheres to the wall and contamination of a next liquid sample is avoided. The individual sample segments are surrounded by and flow in a stream of the immiscible liquid, which can be silicone. An air segment can be provided between sample segments and within the immiscible fluid to insure that successive sample segments do not coalesce.
U.S. Pat. No. 4,253,846 describes a system wherein discrete liquid sample segments are conveyed along a conduit in an immiscible liquid stream, as described in U.S. Pat. No. 3,479,141, above. As in U.S. Pat. No. 3,479,141, cited above, the immiscible fluid fully encapsulates each sample segment which is passed along the system. In such a system, reagents are injected, on a selected basis, into the successive liquid samples as they are passed along a portion of the conduit, so as to react with the same. U.S. Pat. No. 4,259,291, also assigned to the instant assignee, illustrates a mode of introducing sample to establish a stream of alternating gas and liquid segments to which diluent is later added.
Each of the above-described systems does involve the transport of liquid samples along a conduit. However, the overall or total conduit length of such systems is usually not greater than about 10 feet. Also, such systems are characterized in that the liquid samples to be analyzed have been previously collected, usually by technicians, from various sources or patients and brought to a single location for introduction into the continuous-flow system, e.g. an indexing turntable from which the samples are successively aspirated into the system. The gathering of such samples is not only costly and time-consuming, but, also, is a source of human error in respect of sample identification.
Accordingly, whether in a clinical or industrial environment, there is a need for a reliable and inexpensive technique for gathering and transporting samples from remote locations to a centrally located analytical station, without human intervention. Also, for monitoring purposes, as in the case of various industrial processes throughout a manufacturing establishment, it is advantageous to be able to periodically monitor one or more remote locations by having samples of an industrial material analyzed at a centrally located analytical station. Heretofore, it has been necessary to provide an analytical station at each such remote location. The present invention is directed to overcoming such requirements and provides a single, centralized analytical station which can service a plurality of remote stations.